Renowned as the Green Lake, this unusual natural occurrence is the only lake worldwide that changes from a winter park to a deep blue lake in summer. The area functions as a public park with benches, trails, and bridges in winter. But when spring comes, melting snow from the nearby Hochschwab mountains floods the region, producing a lake as pure as twelve meters deep. Underwater paths, chairs, and trees seen through the shockingly clean water give the sunken park an unreal diving experience. Complicated hydrogeological mechanisms carry snowmelt via subterranean karst formations before filling the basin in yearly change. Researchers examine this special habitat to learn how marine and terrestrial settings could alternate periodically and preserve biological equilibrium. Rarely does the water temperature of the lake rise over 7 degrees Celsius, which provides ideal habitat for some specialist alpine aquatic life able to withstand seasonal variations.
